## Metadata - Author: [[Robert Axelrod]] - Full Title: The Evolution of Cooperation - Category: #books ## Highlights - In a Darwinian world, that which survives survives, and the world becomes full of whatever qualities it takes to survive. As Darwinians, we start pessimistically by assuming deep selfishness at the level of natural selection, pitiless indifference to suffering, ruthless attention to individual success at the expense of others. And yet from such warped beginnings, something can come that is in effect, if not necessarily in intention, close to amicable brotherhood and sisterhood. ([Location 93](https://readwise.io/to_kindle?action=open&asin=B00AHFJ5VS&location=93)) - Without their realizing it, many of these rules actually wound up punishing themselves. With the other player serving as a mechanism to delay the self-punishment by a few moves, this aspect of self-punishment was not picked up by many of the decision rules. ([Location 639](https://readwise.io/to_kindle?action=open&asin=B00AHFJ5VS&location=639)) - The sample program sent to prospective contestants to show them how to make a submission would in fact have won the tournament if anyone had simply clipped it and mailed it in! But no one did. The sample program defects only if the other player defected on the previous two moves. It is a more forgiving version of TIT FOR TAT in that it does not punish isolated defections. The excellent performance of this TIT FOR TWO TATS rule highlights the fact that a common error of the contestants was to expect that gains could be made from being relatively less forgiving than TIT FOR TAT, whereas in fact there were big gains to be made from being even more forgiving. The implication of this finding is striking, since it suggests that even expert strategists do not give sufficient weight to the importance of forgiveness. ([Location 645](https://readwise.io/to_kindle?action=open&asin=B00AHFJ5VS&location=645)) - TIT FOR TAT benefits from its own nonexploitability because three conditions are satisfied: The possibility of encountering TIT FOR TAT is salient. Once encountered, TIT FOR TAT is easy to recognize. Once recognized, TIT FOR TAT’s nonexploitability is easy to appreciate. Thus TIT FOR TAT benefits from its own clarity. ([Location 838](https://readwise.io/to_kindle?action=open&asin=B00AHFJ5VS&location=838)) - What accounts for TIT FOR TAT’s robust success is its combination of being nice, retaliatory, forgiving, and clear. Its niceness prevents it from getting into unnecessary trouble. Its retaliation discourages the other side from persisting whenever defection is tried. Its forgiveness helps restore mutual cooperation. And its clarity makes it intelligible to the other player, thereby eliciting long-term cooperation. ([Location 850](https://readwise.io/to_kindle?action=open&asin=B00AHFJ5VS&location=850))